From Wikizilla:

"Hedorah and Godzilla had a final showdown near Mt. Fuji, in which Hedorah achieved his final form, a humanoid, walking pile of sludge. Thanks to his acidic, poisonous body, as well as his lethal eye bolts, Hedorah very nearly put an end to Godzilla in their struggle."

I'm pretty sure Hedorah is dangerous in its final form.